CN1790582A - Contactor assembly for circuit breaker - Google Patents

Abstract

A contactor assembly for a circuit breaker is disclosed. There is provided a contactor assembly, wherein stationary pins fixed to a rotary shaft and supporting one ends of springs and limit pins contacting the upper surface of the movable contactor and supporting the other ends of the springs are connected by link plates, comprising a movable contactor provided on the upper surface of the movable contactor with groove surfaces having a constant first curvature radius and curve surfaces having a constant second curvature radius larger than the first curvature radius. By this, a contact pressure provided by the springs is constant, and a separating position can be maintained when separating the contactor by an electromagnetic repulsive force.

Description

Contactor Assemblies for Circuit Breakers

technical field

This invention relates to molded cased circuit breakers for protecting circuits and load end equipment by automatically opening the circuit when an overload or short circuit occurs, and more particularly to contactor assemblies for circuit breakers.

Background technique

Molded case circuit breakers (known by the acronym MCCB) are installed on switchboards in several electrical systems in factories and buildings. A circuit breaker is used as a switch for supplying or cutting off power to a load terminal in a no-load state, and to cut off power supplied from a power supply terminal to a load terminal so that when a large abnormal current flows due to a short circuit or a ground fault in a load state circuit, protect the circuit and load-side components.

FIG. 1 is a sectional view showing the main internal structure of a conventional circuit breaker. Fig. 2 shows a movable contactor assembly for a conventional circuit breaker, which is a front view showing a state (on state) in which contacts are in contact with each other. Fig. 3 shows a movable contactor assembly for a conventional circuit breaker, which is a front view showing a state of separating contacts (open state).

As shown therein, a conventional circuit breaker 1 includes a molded case 10, within the molded case 10, fixed contactors 9 and 9' mounted at even intervals in the horizontal and vertical directions, rotatably mounted on fixed A rotary type movable contactor assembly 17 between the contacts 9 and 9', a trip mechanism 11 for detecting high current and releasing the circuit breaker, operated automatically by the trip mechanism 11 or by manual handling of the handle, and A switch mechanism 12 for separating the movable contactor 4 and the fixed contactors 9 and 9' and breaking the circuit, and for eliminating the contact 4b of the movable contactor 4 and the contacts of the fixed contactors 9 and 9' Arc suppression mechanism 13 for high temperature and high pressure arc gas generated between 9b and 9b'.

The molded case 10 accommodates the above-mentioned mechanisms, is formed of an insulating material and serves to insulate between mechanisms, between phases and from the outside, and to prevent the material from penetrating into the molded case 10 .

The contacts 9a and 9b are formed at the ends of the fixed contactors, ie, the fixed contactor 9' on the power supply side and the fixed contactor 9' on the load side, and the contact 4b is formed at the end of the movable contactor 4.

A conventional movable contactor assembly 17 includes a rotating shaft 2, rotatably installed between the fixed contactors 9 and 9' for maintaining the on state and the off state and mounted on a cam surface 4c and a cam groove 4d. Between the movable contactor 4 and the fixed contactors 9 and 9' for supporting the movable contactor 4, the limiting pin 19 contacting the cam surface 4c and the cam groove 4d, and a plurality of springs 15 and 16 for The movable contactor 4 is elastically rotated about the virtual rotation axis (rotation center) 2a by the electromagnetic repulsive force generated at each of the contacts 9b and 9b' when a large current flows due to an abnormality in the circuit.

One ends 15 a and 16 a of the plurality of springs 15 and 16 are fixed to the limiting pin 19 , and the other ends 15 b and 16 b are fixed to the rotary shaft 2 . For example, a method of supporting the movable contactor 4 on the rotation shaft 2 around a virtual rotation shaft (rotation center) 2a, although not actually present, is called self-centering.

As shown in Figure 2, the state in which the contact 4b of the movable contactor 4 and the contacts 9b and 9b' of the fixed contactors 9 and 9' are in contact with each other is called "off state", as shown in Figure 3, the movable A state where the contact 4b of the contactor 4 and the contacts 9b and 9b' of the fixed contactors 9 and 9' are separated from each other is referred to as "on state". The state in which the off state is converted into the on state is called separation and disconnection.

As shown in FIG. 2 , in the off state, normal current flows through the circuit, wherein the limiting pin 19 presses the cam surface 4c of the movable contactor 4 by a constant pressure by the tensile strength of the springs 15 and 16, thereby maintaining the movable contactor 4c. The moving contactor 4 and the fixed contactors 9 and 9' are in contact with each other.

On the contrary, as shown in FIG. 3, in the case where a large current flows through the circuit due to a short circuit of the circuit, it passes between the contact 4b of the movable contactor 4 and the contacts 9b and 9b' of the fixed contactors 9 and 9'. The electromagnetic repulsion force, the movable contactor 4 rotates clockwise. At this time, the contact 4b is separated from the contacts 9b and 9b', thereby breaking the circuit. Unexplained numeral 18 denotes a stopper for limiting the rotational range of the movable contactor.

However, in the movable contactor assembly used in conventional circuit breakers, the contact pressure of the springs 15 and 16' is not constant, including when overtravel occurs, stopping the movable contactors 9 and 9' in contact with the fixed contacts. At the contact position of the contactor 4, the rotating shaft 2 rotates farther than the movable contactor 4, the contact pressure of the springs 15 and 16' is further increased, and according to the positions of the limiting pins on the cam surface 4c and the cam groove 4d, Problem with changing contact pressure of springs 15 and 16. Therefore, when the movable contactor 4 rotates apart from the fixed contactors 9 and 9' due to the electromagnetic repulsive force caused by applying a large current, if the electromagnetic repulsive force becomes smaller than the contact force, the movable contactor 4 returns to the same position as the fixed contactors 9 and 9'. The position where the contactors 9 and 9' touch is fixed. Therefore, the current limiting operation fails. Due to this, arcs are continuously generated, so that instantaneous current limiting characteristics cannot be obtained, and serious damage is caused to circuit breakers and load equipment.

Contents of the invention

Therefore, the present invention is directed to solving the above-mentioned problems, and has provided a contactor assembly for a circuit breaker, which maintains a constant contact pressure between the contacts through springs regardless of the rotational position of the rotary shaft at the contact position, and can maintain separate position for a predetermined time without the moveable contactor returning to the stationary contactor after separation and opening of the contacts is complete.

The above objects of the present invention are achieved by providing a contactor assembly for a circuit breaker, comprising: a fixed contactor, a U-shaped first fixed contactor having a power supply connected to the circuit and in horizontal and vertical directions, with the first fixed contactor is separated by a predetermined distance and is connected to a U-shaped second fixed contactor of an electric load on the circuit; a movable contactor having contacts at both ends corresponding to the first and second fixed contactors; and movable to a contact position with the first and second fixed contactors and a disengaged position where the movable contactor is separated from the first and second fixed contactors, the movable contactor having grooved surfaces on each of its upper and lower having a first radius of curvature on the surface so that when the movable contactor rotates separately from the fixed contactor by electromagnetic repulsion between the fixed contactor and the movable contactor, the separated position of the movable contactor can be maintained, and the curved surface , on each of its upper and lower surfaces, continuous with the groove surface, has a second radius of curvature greater than the first radius of curvature; the rotating shaft, rotatably supporting the movable contactor, has an opening portion for When the electromagnetic repulsion force is generated between the movable contactor and the fixed contactor, the independent rotation of the movable contactor is allowed, and further rotation is possible compared with the movable contactor at the contact position where the movable contactor is in contact with the fixed contactor; A central shaft pin passing through the movable contactor and supported at the central portion of the rotating shaft to support the movable contactor on the rotating shaft; a pair of fixed pins fixedly mounted symmetrically to each other around the central portion of the rotating shaft On the axis of rotation; two pairs of link plates, one end of which is rotatably supported on both ends of each of the fixed pins; a pair of limiting pins, rotatably supported on the other end of the link plates and replaceable, or maintain a stop on the curved and grooved surfaces of the movable contactor, depending on the position of the movable contactor; The contact position of the fixed contactor contact provides contact pressure, one end is supported on the fixed pin, and the other end is supported on the limiting pin, wherein the fixing pin and the limiting pin at both ends of the supporting spring are connected by a chain plate, and the limiting pin is located at On the curved surface of the movable contactor with a constant radius of curvature at the contact position, the contact pressure provided by the spring remains constant, and the spring accumulates elastic energy according to the height difference between the groove surface and the curved surface at the contact position, and when passed by the electromagnetic The rotation of the movable contact caused by the repulsive force defines the spring to release the accumulated elastic energy when the pin is on the surface of the groove.

Description of drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

In the picture:

1 is a sectional view showing the main internal structure of a conventional circuit breaker;

Fig. 2 shows a contactor assembly for a conventional circuit breaker, which is a front view showing an on state;

3 shows a contactor assembly of a conventional circuit breaker, which is a front view showing a current-limiting state of separating and disconnecting contacts by electromagnetic repulsion;

4 is an exploded perspective view showing a contactor assembly for a circuit breaker according to the present invention;

5 is an assembly perspective view showing a state of assembling a contactor assembly for a circuit breaker and a perspective view showing a current limiting state of separating and disconnecting contacts by electromagnetic repulsion force according to the present invention;

6 to 8 are sectional views showing the operating state of the contactor assembly for the circuit breaker according to the present invention, wherein FIG. 6 is a sectional view showing the operating state of the contact contact (contact state) state, and FIG. 8 is a sectional view showing a state in which the contacts are separated and disconnected by electromagnetic repulsion force (current limiting operation).

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

First, as shown in Figures 4 and 5, a contactor assembly 100 for a circuit breaker according to the present invention includes fixed contactors 110 and 110', with a U-shaped current-limiting first fixed contactor connected to a power source on the circuit 110 and a U-shaped current-limiting second fixed contactor 110' separated from the first fixed contactor 110 by a predetermined distance in horizontal and vertical directions and connected to an electric load on the circuit. The fixed contact 111 is connected to one end of the first and second fixed contactors 110 and 110'. The contactor assembly 100 includes a movable contactor 120 having contacts 121 at both ends corresponding to the fixed contacts 111 of the first and second fixed contactors 110 and 110', and movable and movable to the first and second fixed contacts 110'. A contact position to be in contact with the second fixed contactors 110 and 110' and a separation position to separate the movable contactor 120 from the first and second fixed contactors 110 and 110'. The movable contactor 120 has a groove surface 124 having a first radius of curvature r1 on each of its upper and lower surfaces, and a groove surface 124 having a radius greater than the first radius of curvature r1 on each of its upper and lower surfaces, continuous with the groove surface 124. The curved surface 123 with the second curvature radius r2.

The rotating shaft 130 included in the contactor assembly of the present invention rotatably supports the movable contactor 120, and has an opening portion 133 for when an electromagnetic wave is generated between the movable contactor 120 and the fixed contactors 110 and 110'. Independent rotation of the movable contactor 120 is allowed when the force is repelled. Here, the independent rotation of the movable contactor 120 means that only the movable contactor 120 is independently rotated in a direction apart from the fixed contactor by an electromagnetic repulsion force caused by applying a large current such as a short-circuit current, and the rotation axis 130 stops, unlike in a trip operation where the movable contactor 120 rotates in a direction separate from the fixed contactor by rotation of the rotation shaft 130 . In a state where the movable contactor 120 is stopped at a contact position where the movable contactor 120 is in contact with the fixed contactors 110 and 110', the rotation shaft 130 may rotate further than the movable contactor 120. That is, even if the fixed contactors 110 and 110' are in contact, the movable contactor 120 is stopped, in the direction in which the movable contactor 120 is in contact with the fixed contactors 110 and 110', that is, as seen in FIGS. 4 and 5 In the counterclockwise direction, the rotation shaft 130 can rotate further.

The contactor assembly of the present invention includes a center shaft pin 140 passing through the movable contactor 120 and supported on a central portion of the rotation shaft 130 so as to support the movable contactor 120 on the rotation shaft 130 .

The contactor assembly of the present invention includes a pair of fixing pins 150 fixedly mounted on the rotating shaft 130 symmetrically to each other around the central portion of the rotating shaft 130 .

The contactor assembly of the present invention includes two pairs of link plates 161 , one end of which is rotatably supported on both ends of each of the fixing pins 150 .

The contactor assembly of the present invention includes a pair of limiting pins 160, which are rotatably supported on the other end of the chain plate 161 and can be replaced, or according to the position of the movable contactor 120, on the curved surface 123 and the groove of the movable contactor 120 The stopped state is maintained on surface 124 .

The contactor assembly of the present invention includes two pairs of springs 170 customized so that one pair corresponds to each side of the rotating shaft 130 to provide contact pressure at the contact locations where the movable contactor 120 and the stationary contactors 110 and 110' come into contact. , one end is supported on the fixing pin 150 , and the other end is supported on the limiting pin 160 . Here, the fixed pin 150 and the limiting pin 160 supporting the two ends of the spring 170 are connected by a chain plate 161, the limiting pin 160 is located in the contact position, on the curved surface 123 of the movable contactor 120 with a second constant radius of curvature r2, and is formed by the spring The contact pressure provided by 170 can be kept constant.

The movable contactor 120 has a vertical elongated hole 122 through which a central shaft pin 140 passes so as to move in a vertical direction about the central shaft pin 140 .

The opening portion 131 of the rotation shaft 130 allowing independent rotation of the movable contactor 120 represents a space formed on the rotation shaft 130 for allowing independent rotation of the movable contactor 120 .

In FIGS. 4 and 5 , unexplained reference numeral 133 denotes a fixing pin hole for inserting and installing the fixing pin 150 , and unexplained reference numeral 134 denotes a spring accommodating groove formed concavely on the rotating shaft 130 to accommodate the spring 170 .

When the springs 170 are accommodated in the spring receiving grooves 134, they do not protrude to the outside of the rotation shaft 130 thereby tightly constituting a contactor assembly for the circuit breaker.

Now, referring to FIGS. 6 to 8, the operation of the contactor assembly of the circuit breaker for power distribution according to the present invention thus constituted will be described.

First, in a normal current-carrying state, that is, a closed circuit state, as shown in FIG. 6, in which the rotating shaft 130 is rotated counterclockwise by power supplied from an opening-closing mechanism (not shown), so that the rotating shaft 130 The supported movable contactor 120 is in contact with the fixed contactors 110 and 110', and the current flows from the power source through the first fixed contactor 110, and through the movable contactor 120, at the load end, through the second fixed contactor 110', to the load .

At this time, the limiting pin 160 is located on the curved surface 123 of the movable contactor 120, thereby stretching the spring 170 as long as the height difference between the curved surface 123 and the groove surface 124, thereby accumulating (charge) elastic energy. ). Therefore, the spring 170 pulls the limiting pin 160 toward the central axis pin 140, and provides a moment so that the limiting pin 160 presses the curved surface 123 of the movable contactor 120 to contact the fixed contactors 110 and 110', that is, counterclockwise in the figure. Rotate the movable contactor 120 in the direction. Therefore, the contact point 121 of the movable contactor 120 and the contact point 111 of the fixed contactors 110 and 110' maintain a contact state. At this time, the torque provided by the spring 170 so that the movable contactor 120 rotates in the direction of contacting the fixed contactors 110 and 110', ie, the counterclockwise direction in the drawing, is referred to as providing contact pressure.

At this time, in the present invention, even when the moving contactor 120 is in contact with the fixed contactors 110 and 110', that is, the rotating shaft 130 is overtraveled, due to this, in the contact direction (counterclockwise in FIG. 6), the rotating shaft 130 is further rotated, and the fixed pin 150 and the limiting pin 160 at the two ends of the support spring 170 are connected by the chain plate 161, and the limiting pin 160 is located on the curved surface 123 of the movable contactor 120 with a constant radius of curvature at the contact position, and is made by the spring 170 The supplied pressure remains constant.

When a large current, such as a short circuit current, flows through the contactor assembly of the present invention at the above position, an electromagnetic repulsive force is generated between the contact 121 of the movable contactor 120 and the contact 111 of the fixed contactors 110 and 110'.

Typically, this electromagnetic repulsion force is greater than the contact pressure induced by the spring 170 when a large fault current is generated, such as a short circuit. Therefore, as shown in FIG. 7 , the movable contactor 120 overcomes the contact pressure and starts to rotate clockwise. At this time, by the elastic force of the spring 170, the limiting pins 160 slide along the curved surface 123 with a constant radius of curvature until they are inserted into the groove surface 124 of the movable contactor 120, and accordingly, the contact direction generated by the spring 170 The torque (contact pressure) is kept constant.

As shown in FIG. 8, in the step of ending the separation and operation, the arc generated between the contacts 121 and 111 of the movable contactor 120 and the fixed contactors 110 and 110' is extinguished, so that the movable contactor 120 and the fixed contactor 120 The contacts 121 and 111 of the contactors 110 and 110' are completely separated mechanically and electronically.

As shown in FIG. 8, when the limiting pin 160 is inserted into the groove surface 124 by the clockwise rotation of the movable contactor 120, the spring 170 is stretched as long as the height difference between the curved surface 123 and the groove surface 124, and Release accumulated elastic energy. Subsequently, the contact pressure caused by the spring 170 becomes zero, or at least less than the electromagnetic repulsion force. Therefore, the state shown in FIG. 8 is maintained in which the movable contactor 120 is prevented from returning to the fixed contactors 110 and 110' and the movable contactor 120 is separated from the fixed contactors 110 and 110'.

Then, the on-off mechanism 12 (refer to FIG. 1 ) receives a trip signal from the trip mechanism 11 (refer to FIG. 1 ) to rotate the rotation shaft clockwise, thereby tripping the circuit breaker for power distribution.

As described above, in the present invention, even if the movable contactor touches the fixed contactor, that is, the rotating shaft overtravels, both ends of the spring are supported by the fixed pin fixed to the rotating shaft and the limit pin connected by the fixed pin and the link plate , and the limiting pin is located on the curved surface of the movable contactor with a constant radius of curvature in the contact position, so that on the curved surface, the contact pressure provided by the spring remains constant.

Furthermore, when the limiting pin is inserted into the groove surface by clockwise rotation of the movable contactor, the spring is stretched as long as the height difference between the curved surface and the groove surface and the elastic energy accumulated is released. Subsequently, the contact pressure caused by the spring becomes zero, or at least less than the electromagnetic repulsion force. Therefore, the movable contactor is prevented from returning to the fixed contactor, and the movable contactor is separated from the fixed contactor.

Claims (3)

1. A contactor assembly for a circuit breaker, comprising: A fixed contactor having a U-shaped first fixed contactor connected to a power source on the circuit and a U-shaped second fixed contactor separated from the first fixed contactor by a predetermined distance in horizontal and vertical directions and connected to an electric load on the circuit fixed contactor; A movable contactor having contacts at both ends corresponding to the first and second fixed contactors, and movable to a contact position with the first and second fixed contactors and the movable contactor with the first and second fixed contactors The separation position where the two fixed contactors are separated, and the movable contactor has a grooved surface with a first radius of curvature on each of its upper and lower surfaces, so that when passing through the electromagnetic repulsion between the fixed contactor and the movable contactor, it can be The disengaged position of the movable contactor is maintained when the movable contactor is rotated separately from the fixed contactor, and the curved surface, on each of its upper and lower surfaces, continuous with the surface of the groove, has a second curvature greater than the first radius of curvature radius; A rotary shaft rotatably supporting the movable contactor, having an open portion for allowing independent rotation of the movable contactor when an electromagnetic repulsion force is generated between the movable contactor and the fixed contactor, and when the movable contactor In the contact position where the contactor is in contact with the fixed contactor, it can be further rotated compared with the movable contactor; a central shaft pin passing through the movable contactor and supported at the central portion of the rotating shaft to support the movable contactor on the rotating shaft; A pair of fixed pins are fixedly mounted on the rotating shaft symmetrically to each other around the central portion of the rotating shaft; two pairs of chain plates, one end of which is rotatably supported on both ends of each of the fixed pins; a pair of limiting pins rotatably supported on the other end of the chain plate and replaceable, or depending on the position of the movable contactor, maintain a stopped state on the curved and grooved surfaces of the movable contactor; and Two pairs of custom springs so that each pair corresponds to each side of the axis of rotation to provide contact pressure at the contact position where the movable contactor contacts the fixed contactor, one end is supported on the fixed pin, and the other end is on the restraining pin supported; Among them, the fixed pin and the limiting pin at both ends of the supporting spring are connected by a chain plate, the limiting pin is located on the curved surface of the movable contactor with a constant curvature radius at the contact position, the contact pressure provided by the spring is kept constant, and the spring is based on the contact position at the contact position The elastic energy is accumulated due to the difference in height between the surface of the groove and the curved surface, and the spring releases the accumulated elastic energy when the pin is positioned on the surface of the groove by the rotation of the movable contactor caused by the electromagnetic repulsion force. 2. The contactor assembly of claim 1, wherein the recessed surface of the movable contactor has a constant radius of curvature. 3. The contactor assembly according to claim 2, wherein the movable contactor has a vertical elongated hole through which the central axis pin passes so as to be movable in a vertical direction about the central axis pin.

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